Telephone-exchange system



F. N. REEVES.

TELEPHONE EXCHANGE SYSTEM.

' APPLICATION FILED sEPr .30. 1918.

1,353,612, PatentedSept. 21,1920.

//1 ken fo r: Fran/r Nfiee ves PATENT QFFECE.

UNITED STATES FRANK N. REEVES, OF NEWARK, NEW JERSEY, ASEiIGNOE 'lO VTEETERN ELECTRIC COMPANY, INCORPORATED, OF NEW YQRK, N. Y., A CCERESRATIQN' OF NEW YQRK.

TELEPHONE-EXCHANGE SYSTEM.

To oZZ whom it may. concern: 7

Be it known that I, FRANK N. REEVES, a citizen of the United States, residing at Newark, in the county of Essex, State of New Jersey, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a 7 full, clear, concise, and exact description.

This invention relates to improvements in automatic telephone exchange systems, and has particular reference to a substation circuit arrangement for use in' connection with impulse sending devices.

Heretofore, in telephone exchange systems wherein a subscriber removes his receiver to initiate a call and then operates the imoulse sending device, the receiver and transmitter have been included in the line circuit while the impulses were being sent, which results in disagreeable clicks in the eceiver and -furthermore the resistance of the transmitter has made the sending of impulses to operate the switching mechanism for extending a call less efiicient, especially when the sending device is applied to a desk stand apparatus and the same is held horizontal or substantially so during the sending of impulses, in which instance the granular carbon in the transmitter will become packed to such a degree that the resistance thereof will prevent the transmission of impulses.

An object of this invention is to avoid the above dificulties by providing an improved substation circuit whereby clicks due to the sending of impulses will be excluded from the receiver and the resistance of the transmitter shunted when the sending device is operated.

The inventive idea involved is capable of receiving a variety of expressions, one of which, for the purpose of illustrating the invention, is shown in the accompanying drawing; but it is to be expressly understood that said drawing is employed merely to facilitate the description of the invention as a whole and not to define the limits thereof, reference being had to the appended claims for this purpose.

The drawing illustrates diagrammatically a substation circuit and associated sending device arranged in accordance with the invention.

In the drawing, 1 and 2 designate the usual line conductors in which a ringer apparatus 3 is placed in series with a con- Specification of Letters Patent.

denser a. The switchhcok 5 supports the rec iver and normally opens a bridge across the conductors 1 and 2 which is closed upon he removal of the receiver from its hook.

elephone transmitter 7 and primary induction coil 8 are also included in the normally open bridge across said conductors and a transmitter cut-out key 9 may be emplo; ed to short-circuit the transmitter during the use of the receiver if so. desired. A secondary induction coil 10 and the receiver 6 are arranged to be brought into circuit upon removal of said receiver from the switchhook 5. A

The impulse sending device associated with the substation circuit may be of the type shown in the patent to O. F. F orsberg, 1,161,854, dated November 30, 1915, but it will be understood, of course, that other types of sending devices may be employed as well. Briefly, the device as shown includes a dial 11 mounted upon an axis 12 which also carries an impulse wheel 13 and an arm let, the latter engaging a contact spring 15 when the sending device is in its normal position, whereby said contact spring will be engaged with the contact 16 to close the substation circuit at this point. The sending device further includes a small bell crank lever 17 adapted to be engaged by the teeth of the impulse wheel 13, after the dial 11 has been initially moved and is returning toward its normal position, to vibrate the contact spring 18 to transmit the desired number of impulses.

Assuming that the subscriber has removed the receiver 6 from the switchhook 5 to initiate a call, the substation circuit will be closed from grounded battery at the first switching mechanism (not shown), conductor 1, contact 20, contact spring 18, transmitter 7, switchhook 5, primary coil 8 and conductor 2 to ground at said switching mechanism. At this time the circuit for receiver 6 will be closeo at contact 16 and will also extend through the transmitter 7, but upon the initial rotation of the dial 11 in, setting the sending device, arm 14 will disengage contact spring 15 and break the receiver circuit at contact 16, whereupon said contact spring will engage contact 21. Simultaneously, the transmitter 7 will be shunted and the circuit extended from contact spring 18, through conductor 22, contact 21, contact spring 15, switchhook 5 and pri- Patented Sept. 21, 12320. Application filed September 30, 1918. Serial No. 256,311.

mary coil 8 to conductor 2. After being set to transmit the desired number oi-iinpulses, the dial is returned toward its normal position by thespring 23, and in so doing lever 17 is actuated to make and break the circuit at contact 20 until said dial 11 has returned to normal, whereupon the arm 14: Will again engage contact spring 15 and definitely break the shunt circuit and close the receiver and transmitter circuits at contact 16.

'It will-thus be obvious that during the operation of the sending device, the receiver circuit. will be open so that clicks due to the transmission oi"v impulses Will be excluded from. said receiver and the transmitter Will be shunted so its resistance will not hinder the transmission of impulses.

Although the circuit arrangement has been described in connection With an automatic system, it wvill be understood that samemay also lie-employed in connection with a sen'iieutomaticsystem, in which instance the circuit arrangement and sending device would be placed at an operators position.

LVVhat' is claimed is:

1. Ina substation circuit arrangement'for telephone :exchange systems a receiver, a transmitter, normally open circuits for said transmitter-and said receiver, aswitch for closingsaid-circuits,an impulse sending device having a definite normal position,

erated during the last-mentioned movement of said device for sending impulses, a contact operated during said movements of said device for opening the circuit of said receiver, and another contact operated during saidnrovements ofsaid device for shunting said transmitter.

2. In a substation circuit arrangement for telephone exchange systems, a receiver, a transmitter,' normallyopen circuits for said receiver and transmitter, means for closing said circuits, an impulse sending device, means actuated by said device ror transmitting impulseaand means actuated during the operation of said sending device for-opening the receiver circuit and shunting the transmitter circuit.

illn-a tele 'ahonesubstation circuit, a receiver, a circuit therefor, a transmitter, a shunt circuit therefor, 1211i impulse sending device andcontacts controlled by said device i or openings-aid receiver circuit and closing said shunt circuit Whenever said device is moved fromnormal.

=In witness whereof, I here-untosubscribe my name this 25th day of September A. 1)., 1918.

FRANK N. REEVES 

